2.13 Open Clinker Piles

Comment: Several commenters (2845, 2864, and 2874) stated that in the past, EPA considered regulating open storage piles; however, in the 2001 settlement agreement and subsequent follow-up letter from EPA to American Portland Cement Alliance that settled litigation over the 1999 NESHAP final rule, EPA agreed not to regulate fugitive emissions from open or unenclosed material stockpiles or haul roads. Although, the proposal asserts that open clinker storage piles located at two facilities had measurable emissions of hexavalent chromium, the emissions and the ambient concentrations in the area surrounding cement facilities were low. The ambient concentrations are also miniscule when compared to benchmark regulatory standards. Also, several California air quality district have decided against regulating hexavalent chromium emissions from cement plants due to the lack of risk. For these reasons, it would be inappropriate to define open clicker storage piles as affected sources under the NESHAP.

Response: At proposal we noted that open clinker piles were currently unregulated, and that hexavalent chromium emissions had been detected in fugitive dust from these piles. See 74 FR at 21163. We requested comment and information as to how common the practice of open clinker storage is, appropriate ways to detect or measure fugitive emissions (ranging from open-path techniques to continuous digital or intermittent manual visible emissions techniques), any measurements of emissions of hexavalent chromium (or other HAP) from these open storage piles, potential controls to reduce emissions, or any other factors we should consider.

Commenters did not provide data on this practice. Industry commenters stated emissions were de minimis and should not be regulated. Other commenters noted that the fact that we know these sources emit HAP is sufficient to necessitate regulation.

We agree that these operations do emit HAP and that regulation of these sources is necessary. See National Lime, 233 F. 3d at 640 (upholding EPA position that de minimis exceptions are not to be read into the MACT standard setting process). Because the emissions in question are fugitive dust for which measurement is not feasible since (by definition) the emissions are not emitted through a conveyance or other device which allows their measurement (see section 112 (h) (1) and (2)(A)), we are incorporating the work practice standards and opacity emissions limits contained in Rule 1156 as amended by the South Coast Air Quality Management District on March 6, 2009 and incorporating them into this rule. There are only two plants which EPA can state definitively have open storage piles and are complying with Rule 1156, so these existing regulatory standards would constitute a floor level of control (and EPA does not believe beyond-the-floor controls are needed, since utilizing some type of enclosure should well control fugitive emissions).

Industry commenters also maintained that regulation of open storage piles would violate a 2001 settlement agreement between EPA and the industry in which EPA agreed that the 1999 rule did not apply to fugitive emission sources. But nothing in that settlement agreement prevents EPA from amending its regulations if it is appropriate to do so (nor could EPA legally bind itself in such a way). The agreement in fact states that “[n]othing in this Agreement shall be construed to limit or modify EPA's discretion to alter, amend, or revise, or to promulgate regulations that supersede, the regulations identified in section III of this Agreement.” Consequently, EPA’s action today amends the current regulation, and does not violate any provisions of the settlement agreement.

Comment: Several commenters (2816, 2911, and 3162) agreed that open clinker piles should be included in the regulation. Commenter 2816 noted that the Agency is already regulating enclosed clinker piles, and the Agency has noted measurable emissions of hexavalent chromium due to fugitive emissions. The commenter stated that while it may be more difficult to control fugitive emissions, it does not relieve either the industry or the Agency from reducing to the maximum degree feasible emissions from this source. Commenters 2816 and 3162 recommended that EPA should review the rules adopted by the South Coast Air Quality Management District and consider adopting similar requirements for open clinker piles.

Response: EPA has adopted this approach in the final rule.

Comment: One commenter (2864) stated that EPA should set work practice standards in the event that EPA is compelled to regulate open clinker piles.

Response: EPA has done so in the final rule.

Comment: One commenter (2898) stated that the rule should cover all emissions of hexavalent chromium from a cement manufacturing facility that constitutes a major source, including emissions from storage units, conveying system transfer points, and fugitive emissions, including those from open clinker piles.

Response: The final rule includes provisions for clinker piles. See preamble for more discussion.